A double pump of this construction has already been disclosed in DE-OS 41 03 986. For accommodation of the radial piston pump, this design has one casing which at the same time forms a face plate for the pump set of the vane-cell pump. An aperture in the casing includes a ring insert for the delivery piston. A casing lid closes said aperture. Therefore, there are at least two separations for sealing the casing containing both pump systems, namely, the separation on the casing lid and the separation between the face plate of the cup-shaped casing and the pump set of the vane-cell pump. Sealing rings are inserted in both said separations.